Diurnal prolactin changes in human cerebrospinal fluid.

Area of Science:

• Neuroendocrinology
• Clinical Chemistry

Background:

• Prolactin (PRL) is a key hormone with known diurnal variations in serum.
• Understanding PRL dynamics in cerebrospinal fluid (CSF) is crucial for neurological and endocrine research.

Purpose of the Study:

• To investigate diurnal variations of prolactin (PRL) concentration in human cerebrospinal fluid (CSF).
• To compare the 24-hour secretory patterns of PRL in CSF and serum.

Main Methods:

• Collected blood and ventricular CSF samples every 2 hours during the day and hourly during the night from eight adult male patients with hydrocephalus.
• Analyzed PRL concentrations in both CSF and serum over a 24-hour period.

Main Results:

• CSF PRL levels demonstrated significant nyctohemeral variations, with lower concentrations during the day and higher levels at night.
• These CSF PRL variations closely resembled the diurnal changes observed in serum PRL levels.
• Six patients with normal serum PRL patterns showed similar 24-hour CSF PRL profiles, while two with altered serum patterns did not exhibit significant CSF PRL variations.

Conclusions:

• The study confirms the existence of diurnal variations in human CSF PRL content.
• CSF PRL secretory profiles are closely related to the 24-hour changes in serum PRL levels.
• These findings suggest a coordinated regulation of PRL secretion between the central nervous system and peripheral circulation.